A known coil form is described in German Offenlegungsschrift No. 32 36 345. In this known coil form, flat contact elements are inserted parallel to the axis of the coil form in fastening grooves provided on the fins. The contact elements are provided with a clamping slot, into which the respective winding ends are inserted for connection. The width of each clamping slot must be adapted to the wire diameter of the corresponding winding end. Thus. if the wire lead diameters are different, differently made contact elements are required.